# FileUpdateNotificationHandler.java

    /*
     * Copyright (c) 2005-2014, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     * WSO2 Inc. licenses this file to you under the Apache License,
     * Version 2.0 (the "License"); you may not use this file except
     * in compliance with the License.
     * You may obtain a copy of the License at
     *
     * http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing,
     * software distributed under the License is distributed on an
     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     * KIND, either express or implied.  See the License for the
     * specific language governing permissions and limitations
     * under the License.
     */

    package org.apache.synapse.transport.dynamicconfigurations;

    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.synapse.transport.nhttp.NhttpConstants;

    import java.io.File;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Timer;
    import java.util.TimerTask;

    /**
     * Periodically checks on configuration file updates and notify respective listeners
     */
    public class FileUpdateNotificationHandler extends TimerTask {

        private static final Log log = LogFactory.getLog(FileUpdateNotificationHandler.class);

        private long fileReadInterval = NhttpConstants.DYNAMIC_PROFILE_RELOAD_DEFAULT_INTERVAL;

        private List<DynamicProfileReloader> profileReloaders;

        /**
         * Constructor with file read interval as the input
         *
         * @param sleepInterval long value in milliseconds
         */
        public FileUpdateNotificationHandler(long sleepInterval) {

            //Cannot configure a value less than the minimum interval
            if (sleepInterval > fileReadInterval) {
                fileReadInterval = sleepInterval;
            }
            profileReloaders = new ArrayList<DynamicProfileReloader>();
            scheduleTimer(fileReadInterval);
        }

        @Override
        public void run() {
            long recordedLastUpdatedTime;
            long latestLastUpdatedTime;
            String filePath;
            File configFile;

            for (DynamicProfileReloader profileLoader : profileReloaders) {

                recordedLastUpdatedTime = profileLoader.getLastUpdatedtime();
                filePath = profileLoader.getFilePath();

                if (filePath != null) {
                    if(!profileLoader.isInvokedFromSchedule()){
                        if(log.isDebugEnabled()) {
                            log.debug("Bypass the scheduled loading cycle of SSL profile since " +
                                      "already loaded from JMX invocation : file path - " + filePath);
                        }
                        profileLoader.setInvokedFromSchedule(true);
                        profileLoader.setLastUpdatedtime(System.currentTimeMillis());
                        continue;
                    }

                    configFile = new File(filePath);

                    try {
                        latestLastUpdatedTime = configFile.lastModified();

                        if (latestLastUpdatedTime > recordedLastUpdatedTime) {
                            profileLoader.setLastUpdatedtime(latestLastUpdatedTime);
                            //Notify file update to the respective file loader
                            profileLoader.notifyFileUpdate(true);
                        }
                    } catch (Exception e) {
                        if(log.isWarnEnabled()) {
                            log.warn("Error loading last modified time for the SSL config file. Updates " +
                                      "will not be loaded from " + filePath);
                        }
                    }
                }
            }
        }

        /**
         * Register listeners for file update notifications
         *
         * @param dynamicProfileReloader Listener to be notified
         */
        public void registerListener(DynamicProfileReloader dynamicProfileReloader) {
            profileReloaders.add(dynamicProfileReloader);
        }

        /**
         * Schedule the handler with given interval to check files for changes
         *
         * @param interval Long time interval for the timer
         */
        private void scheduleTimer(long interval) {
            Timer timer = new Timer(true);
            timer.scheduleAtFixedRate(this, interval, interval);
        }
    }